Pneumatic die-casting machine



N. LESTER PNEUMATIC D-IE CASTINGIACHINE June 19. 1928.

Filed July 2. 1926 4 Sheets-Sheet 1 June 19, .1928.

N. LES TER PNEUIATIC DIE CASTING MACHI! Filed July 2, 1926 4 Sheets-.Shet 2 .wwmw

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'N. LESTER I PNEUKATIC DIE CASTING MACHINE I 4 Sheets-Span 3 Filed July 192% u June 19, 1928. 1,673,832

N LESTER PNEUMATIC DIE CASTING MACHINE Filed July 1926 4 sheet -sheet 4 Patented June 19; 1928.

UNITED STATES NATHAN LESTER, 0F WORCESTER, MASSACHUSETTS.

PNEUMATIC DIE-CASTING MACHINE.

Application filed July 2,

This invention relates to a machine for casting metals and is particularly adapted for what is ordinarily known as die cast- The principal objects of the invention are to provide a separable mold with means for closing it and opening it by air pressure and with means whereby when it is opened the casting will be ejected by the die operating means; to provide pneumatic arrangements with controlling means by which the proper sequence of operations is caused to take place necessarily and without any attention on the part of the operator except to turn a crank; to provide a casting pump in which the nozzle will enter-the sprue in such a way as to prevent the formation ofa projection thereon so that the casting can be removed; to provide a movable pump adapted to be submerged in the metal in the melting pot when not in casting position so as to keep it heated and filled with metal and adapted to be moved readily to-casting position by the rotation of the same handle which has been mentioned above and at the proper time; and to provide other improvements in the various parts so as to get accurate adjustment and perfect .timing of the various features of the device and to prevent any chance of the parts not working in their proper order.

Other objects and advantages of the invention will appear hereinafter.

Reference is to be had to the accompany-' in drawings in which ig. 1 is a side view of a die casting machine constructed in accordance with this invention and shown in the position in which a casting is being made;

Fig. 2 is a plan of the operating means for the dies shown in position with the dies closed but omitting the dies themselves;

Fig. 3 is a similar View showing the position of the parts with the'dies full open;

Fig. 4 is a side view of a detail 0 an adjusting device with parts in section on the line 4:4 of Fig. 2;

Fig. 5 is a sectional view on the line 55 of Fig. 2;

Fig. 6 is a longitudinal central sectional view of the controlling means for the inlet and exhaust of air under pressure for operating. the machine;

1 s. 7, 8 and 9 are views of the cams whic control the operation of the pump 1926. Serial No. 120,203.

shown in three different positions as indicated on the figures themselves;

Fig. 10 is a side view of the pump showing the opposite side from that illustrated in Fig. 1 and showing it in noncasting position;

Fig. 11 is an end view of the same but with the pump in the same position as shown in Fig. 1;

Fig. 12 is a plan, partly in'section,-of one of the pivot constructions; and

Fig. 13 is a sectional view of the arrangement at the top of the pump for preventing metal being drawn over into the air pipes.

Referring first to Fig. 1, the machine em-- bodies a frame 10 on which are located a stationary plate 11 against which one of the dies 12 is adapted to bear and a slidable plate 13 carrying the other die 14. The frame is completed by an end piece 15 whichis adjustable by means ofbolts and is secured to the end piece 11 by threaded rods 16. Also secured to these end. pieces are guide rods 17 for the plate 13. The frame 10 has ways 18 on which this plate 13 slides and the plate has a projection 19 extending to the rear, furnishing a solid base for it.

Supported by the end piece 15 is a cylinder 20 having therein a piston, 21. Movable with the piston is a rod 22 which carries a head 23 fixed to it but adjust-able by means of a screw collar 24. \Vith this head I connect two links 35 on opposite sides which are pivoted to bell cranks 36. One end of each bell crank is pivoted at 37 to a stationary bracket or projection on the end piece 15. The third pivotal point of each bell crank 36isconnected with a lever 38.

These levers are connected .with two links 39 pivoted on the sliding plate 13.

It will be noticed that these levers 38 and and 41 which, when the arts are in the extreme position shown in ig. 2, abut against each other and prevent the link and lever constructions from passing beyond' the dead center, thus limiting the action in that manner. The levers 38.are pivoted to the bell crank 36 and the link 39 at their extreme ends, but in the middle they are pivoted to a second head 42 which is centered on the piston rod 22, but slidable with respect to it. This head is provided with a plurality of ejectors 43 in the form of rods or plates. These normally while in casting position,

7 ion is held in place by another stud 48 as shown in Fig. 5. In this way, the rod 46 can be adjusted back and forth and it is provided with a link 49 connected with the pump for operating it as will appear.

For the purpose of operating and controlling the parts by compressed air, it provide a controlling shaft 50 with a crank 51 by which it can be rotated. This shaft is provided with aseries of four cams 52, 53, 54 and 55. On each cam rests a spring compressed rod having a valve at the top. These valves control ports in a casing 56 above. This casing is provided with a space 57 for receiving air under pressure from an air inlet pipe 58 from any desired source. This space 57 is provided with two ports 59 and 60 adapted to be closed by the valves operated by two of the cams 53 and 54 to let the air down into either one of two spaces 61 and 62. From the space 61 the outer end of the cylinder 20 for the purpose of forcing the piston forward and closing the dies. From the space 62, the air is free to pass through a pipe 64 to the other side of the cylinder 20 to open the dies. The

around except for a notch 67 at one point.

On a shaft68 below there is another cam 69 which is of general circular form but also with a notch 70 of-the same size and Shape as the notch 67. Each of these notches, as will be observed from comparison of Figs. 7 8 and 9, is of such shape that the other cam can rotate'when in registration with that notch, and not otherwise, that is, each notch is of the shape of an arc of and 68 have their axis at a distance apart less, by the width of one of the notches, than the sum of a. radius of the two .cams.

In the position shown in Fig. 8, either cam can be turned from its position, but in the positionsshown in Figs. 7 and 9 only one cam can turn. Thecam 69 also has an: other notch 71 which co-operates with a pin .72 to constitute a stop. This cam simply oscillates the length of this slot and cannot;

messes move beyond it. The shaft 68 is oscillated by an arm 68 projecting from it.

On the shaft 68 are a pair of cams 73 and 74 which operate valves above on spring-- pressed stems as'in the other case. These valves connect another air inlet 75 with a pipe 76 when the cam 74 closes its valve and the cam 73 opens the other. In the position shown in Fig. 6, the air cannot pass to the .pipe 7 6 but only to the exhaust 77.

The pipe 7 6 passes either directly, or preferably through flexible hose, to a three-way chamber 78 which is of considerable importance. This comprises a straight passage which is closed by a plug 79 at the top directs the air in the chamber '78.directly into a pneumatic pump 81. The pipe 76 enters the chamber 78 at one side and below the center. Therefore, when the compressed air has been flowing into the pump.

and opens into a pipe 80 atthe bottom which which is provided with metal therein. and I then is suddenly shut off and exhausted, the

, flux caused by-the sudden reduction in preschance to splash or flow into the pipe 76.

This pneumatic pump 81 comprises merely a casing with a nozzle 82. It is filled by dipping the nozzle down into the metal in the position shown in Fig. 10 and exhausttwo valves connectedvwith the cams 52 and ing the air from the interior of the pump which will be replaced by metal. The metal is forced out of it into the mold in the position shown in Fig. 1. It is mounted to swing in the following way: The melting furnace 82 is provided with a bracket 83 on which is pivoted a link 84 connected by a link 85 with a'pivot stud 86 on the pump itself. The furnace is provided with two brackets 87 which project upwardly and have open bearings 88 at the top in which is located .a shaft 89. This shaft is provided with two links 90 pivoted freely thereon but supported thereby and extending down to the same stud 86 and supporting the circle ofthe other cam. The shafts 50' \i the pump 81 therefrom, but allowing it to swing. It will be understood that the arm 84 is fixed to a shaft 91. on which is fixed another arm 92 con'nected with the operating Rue 9 11, and .its conical end fill the end of that hole to prevent the formation of a wider area on the sprue at the outer and than at any other part, the following mechanism is provided: On the furnace 82 is a shaft 96 mounted in suitable bearings and carrying a plate 97 which can be adjusted by screws 98 to have the proper angle so that an arm 99 thereon will be located in the proper position. This arm is provided with a transverse stud 100 which is adjustable longitudinally as indicated in Fig. 11 and which receives a'downwardly openingrest or hearing 101 on a projection 102 fixed to, or cast integral with, the pneumatic pump 81. This arrangement of the parts 91, 89 and 100, together with the location of the end of the rod 49 with respect to the plate 13, allows of the proper operation of the pneumatic.

pump 81 from thefilling position shown in Fig. 10 to casting position shown in Fig. 1 and back again.

- The operation of the machine is as follows: Vith the mold open as shown in Fig. 3, and the pump in the position shown in Fig. 10, the crank 51 is turned a half revolution from the position in which the handle is vertically above t-he'shaft to its opposite position in which it is vertically below it. It will be noted that the valves are in the position shown in Fig. 6, the dies being open and being held open by the air in the pipe 64, Now the first effect of the turning of the handle in this position is toclose the valve operated by the cam 54 and to open the valve operated by the cam 55 to release the air from in front of the piston 21. Then the valve controlled by the cam 52 is closed and the valve controlled by the valve 53 is opened to allow the air to be forced through the pipe 63 into thecylinder behind the piston. The result of this is to move the parts from the position shown in Fig. 3 to the position shown in Fig. 2. This forces forward the sliding plate 13, closes the dies, and withdrawsthe ejectors 43. The movement of the plate 13 forward actuates the rod 49 to swing the pump 81 upwardly. As it reaches the upward limit of its stroke, it also moves forwardly through the straightening out of the construction formed of the arm 84 and the link 85 and forces the nozzle 82 directly into the sprue opening in the plate-11. At the same time the crank 51, having now reached the bottom, the notch 67 will have come into register with the notch from the position shown in Fig. 7

into that shown in Fig. 8. Now the handle on the shaft 68 which is pinned to the cam 69 is turned to bring this shaft and cam from the position shown in Fi 8 around to that shown in Fig. 9. This a mits air to the pneumatic pump 81 as will be obvious. Now the metal is forced into the mold by this air. The parts are left in this condltion a very short period, just long enough for the casting to chill and retain its shape. Then the handle 68 is turned back and the air released from the top of the metal in the pump and then exhausted at 77. Now if at this time the metal rushes up the pipe 80, it will be caught in the chamber 78 and drop back into the pump as stated above. This having been accomplished, the crank 51 is turned the rest of the way around the circle to its original position. Thisresults in the opposite action, the closing the valve over the port 59 and the opening of the exhaust valve to the position shown in Fig. 6 so as to release the air from that side of the'piston in the cylinder 20. Immediately the other two valves assume the positions shown inthat fi are and the compressed air is forced throug the pipe'64 to draw back the piston. This restores the parts to the position shown in Fi 3 and it will be seen that the ejectors 43, although drawn back slightly, are not drawn back as much as the plate 13. Therefore the casting-in the mold is ejected by this action although the die 14 is attached to the plate 13 and drawn back with it.

It will be seen therefore that the dies are manipulated to open and close simply by the turning of the handle '51 around 360 and that the control of the air to the pump is also accomplished in a very simple way and controlled absolutelyby the positionof the handle 51. The pneumatic pump is moved bodily under the control of the handle 51 and the location of the several points of support and connections which have been shown. It is forced to assume the different positions in proper sequence without any attention on the part of the operator except to operate the handles 51 and 68' The casting is released from the mold on account of the arrangement of the nozzle of the pump and the ejecting devices which have been described in full, and this ejection is not left to chance but is made positive by the ejectors which will forcev it out, even though there might be something to cause it otherwise to stick. The whole operation is very simple and the machine itself is reduced to a small number of parts and yet has all the safety features which are necessary in these machines.

AlthoughI have illustrated and described only-a single form of the invention I am aware of the fact that modifications can he -of.-a mold formed of two dies, one connected with each of said plates, said mold having a sprue hole through the back, means for moving the movable plate away from the fixed plate, an ejector projecting through the movable plate into one of the dies and to the edge of the mold cavity, and means whereby when the movable plate is drawn back, said ejector will be drawn back automatically and continuously but more slowly, whereby the ejector will project against the casting and eject it from that die;

2. The combination with a two die mold, a rod, and means for reciprocating said rod,

of a head fixed on the rod, a pair of links connected with the head, a pair of hell cranks each having three pivotal points, one connected with one of said links and one with a stationary point, levers connected with the other point of each bell crank, a link pivoted to the other end of each lever and to'one die, a second head freely slidable and having an ejector for ejecting a casting from the mold, said'second head being pivoted to said levers, whereby when the rod is withdrawn the second head will be withdrawn but at a slower rate so that the ejector will project further and eject the casting.

3. The combination w1th means for supporting a two die mold, comprising a reciprocable plate, a rod, and means for reciprocating said rod, of a head fixed on the rod, a link connected with the head and extending backwardly therefrom, a lever, means for connecting the link with the lever for operating the latter, a link pivoted to the other end of the lever and to the reciprocable plate, a second head freely slidable on said rod and having anejector thereon for ejecting a casting from the mold, said second head being pivoted to said lever, whereby when the rod is withdrawn the second head will be withdrawn but at a slower rate so that the ejector will project further through the sliding plate and eject the casting. j

'4. In a die casting machine, the combination with two stationary plates and a reciprocable plate arranged parallel with each other, dies carried by one of the stationary plates and the reciproeable plate and located between them, a cylinder carried by the other stationary plate having a piston therein and a rod, of ejectors extending into the reciprocable plate and into the mold cavity for stripping the castings therefrom when this plate is withdrawn, and a 'lever and link construction operatedby the movement of said rod for projecting the ejectors into the dies as the reciprocable plate is withdrawn to separate the dies at a rate of speed different from thatof the reciprocable plate.

5. In a die casting machine, the combination of a stationary plate'and a reciprocable plate, dies carried by the plates and located etween them, a cylinder, a piston therein, a piston rod, an ejector extending into the. reciprocable plate and into the mold cavity for stripping the casting therefrom when this plate is withdrawn, and means operated by the movement of said rod for projecting the ejector into the diesas the reciprocable plate is withdrawn to separate the dies at a rate of speed different from that of the reciprocable plate. p

6. In a die casting machine, the combination of a pair of dies, 9. cylinder having a piston for opening and closing the dies, an operating shaft having-means thereon for introducing fluid into thecylinder and opening and closing the dies as the shaft is rotated through a complete revolution, a cam on said shaft having a notch therein,,a second shaft oscillatably mounted, a cam on the second shaft and having a notch therein, said notches being so related to each other that neither cam can turn except when in registration with the notch of the other cam,

and means operated by the last named shaft for causing metal to be introduced into the mold.

7. In a die casting machine, the combination of a mold in two parts, means for opening and closing the mold, an operating shaft for controlling the operation of said means, a cam on said shaft having a notchftherein, a second shaft having a handle thereon for swinging it, a cam on the second shaft having a notch therein, said notches being so related to each other that neither cam can turn except when in registration with the notch of the other cam, and means operated by the last'named shaft for casting metal in the mold. 8. In a die casting machine, the combination with an operating shaft and a cam thereon of circular form and having an arcuate notch at one'point, of a second shaft parallel therewith having a handle for oscillating it, a second circular cam on the second shaft having an arcuate notch therein, each notch being arranged to permit the other cam to rotate when in registration therewith and to prevent it at other times, the second cam having a limiting notch, and a stop pin in the limiting notch for controlling the 0scillation of the shaft.

9. In a die casting machine, the combination with an operating shaft and a cam thereon of circular form and having a notch at one point, a second shaft having means for oscillating it, a second cam on the second shaft having a notch therein, each notch being arranged to permit the other cam to rotate when in registration therewith and to prevent it at other times, the second cam having a'limiting notch, and a stop pin to control its oscillation, of a pair of cams on the secondshaft, and valves operated by said cams for controlling the supply ofcom- .pressed air to introduce metal into the mold zvhen its cams are turned to the proper posi- 10D. t e

a ing it, a cam. fixed on the shaft having a notch in its circumference, a stop pin cooperating withsaid notch for limiting the oscillation of the shaft, said cam having another notch therein, an operating shaft, a

In cam on the operating shaft having a notch of such a nature that neither cam can turn when its last named notch is in engagement with the circumference of the other cam, a compressed air supply, a pneumatic pump m and means whereby the pump is prevented metal into the mold or from discharging metal except when the second cam is in a predetermined position.

11. In a die casting machine, the combination of a pneumatic pum ie, a controlling shaft having a handle thereon for oscillating it, a cam fixed on th shaft having a notch in its circumference, an operating shaft having a cam with a notch, each notch fitting 115 the circumference of the other cam and the shafts being at a distance apart less than the combined length of a radius of each cam so that neither cam can turn when its notch is in engagement with the circumference JD with the other cam, a compressed air supply,

a pneumatic pump and means controlled by the first named shaft for regulatin the admission of air from said pump an haust therefrom so that the ump' cannot disg charge metal except when t e second cam is in a predetermined position and the handle can be turned only at that time for operating the shaft.

12. In a die casting machine,the combination of a pneumatic pump for introducing metal into the mold or die, a controlling shaft having a handle thereon for oscillatpump for the purpose described, of a pipe ing it, a cam fixed on the shaft having a notch in its circumference, an operating shaft having a cam with a notch, each notch fitting thecircumferenceof the other cam and the shafts being at a distance apart less than the combined length of a radius of each cam.

13. The combination with a pneumatic for introducing 'air under pressure therein, and a chamber above the pump and com -municating therewith at the bottom of the chamber, said chamber'having a boss int which the pipe extends, located materially below the top of the space in said chamber, whereby, when, the air is out off, the, metal from the pum cannot be forced out of said pipe but can forced u in'said chamber only in a direction to ill back into the interior of the pump. V I 14. In a, die casting machine, the combination with a movable die, of a rod connected for introducing the exwith said die to be moved therewith, a

tion of a two part mold, one part movable 'in- 7 to closed position, a rod connected with said .partto be moved therewith, a swinging sup port, means connected with said rod for turning the swinging support on thataxis, a

neumatic pump pivoted on and supported y said swmgingsupport at one end, and means for supporting and guiding the other end to move .the nozzle' of the pump into casting position when the mold closes.

16. The combination with a neumatic pump for supplying metal to a mo (1, having a nozzle below the level of the metal for the purpose of filling the pump when it is vented, of a shaft, two arms projecting from said shaft, a rod" connected with one of said arms and arranged to be 'moved when, the mold is closed to move the shaft, a link connected to the other arms, a supporting link pivoted above and connected with the first named link and also connected with the pum for supporting it, and means for cont l'olhng the position of the pump and its nozz e. v 17. The. combination with a pneumatic pump provided with a nozzle movably located below the level of the metal in a melting pot to fill the pump when it is vented, of a shaft, two arms projecting from said shaft, a rod connected with one of said arm, means for moving the rod, a link connected to the other arms, a supporting link-pivoted above and connected w1th the first named link and also pivoted to the pump for supporting it, said pump having a projection exten ing upwardly therefrom having an open bottom bearing, a stud located .in said bearing, a pivoted arm on which the stud is mounted, and a pivoted plate adjustable about its piv-i 0t and connected with the last named arm v for controlling the position of the pump and v 18.. Tha combination with a pneumatic pumpnpirovidedwitha nozzle, of a su porting i pivoted above and connecte with the pump for supporting it, said pump 'having a projection extendmg u wardly there- Qfrom having an open bottom caring, a stud located in said bearing, a pivoted arm on which the stud is mounted, and a-pivoted plate adjustable about its pivot ,and connected with thelast named arm' for controlling the position of the pump and itsnoz-zle.

In testimony whereof I have hereunto affixed my signature,

' NATHAN LESTER. 

